The present invention relates to extension ladders including adjacent relatively slidable ladder sections and more particularly to rung locks for holding movable fly ladder sections in a selected longitudinal position with respect to adjacent ladder sections, which usually are the stationary or base ladder sections, and to a unique latching structures which can be associated with the rung locks.
Numerous mechanisms for engaging the rungs or stations of an extension ladder to lock a movable fly ladder section to a base section are generally known in the ladder industry. In this regard attention is directed to the rung locks disclosed in such long expired U.S. Pat. Nos. 613,848, issued to F. S. Seagrave on Nov. 8, 1898; 802,017, issued to F. T. Newton on Oct. 17, 1905; British patent No. 748,515, issued to C. W. Catless on May 2, 1956; and to more recently issued U.S. Pat. Nos. 4,229,306 issued to H. G. Hawkins on Nov. 10, 1981 and 5,117,943, issued to T. J. Schmitt et al on Jun. 2, 1992. Each of these aforedescribed patents teaches a rang lock frame pivotally mounted on the side rail of a fly section of an extensible ladder, the frame being shaped and sized to engage adjacent rungs of adjacent, relatively movable ladder sections so as to hold relatively movable ladder sections together in a selected longitudinal position.
It also has long been known to further recommend tying the bottom fly to an adjacent base rung with a rope, such an augmenting recommendation usually being printed on labels attached to extension ladders.
The present invention provides a unique rung lock frame and latching structure assembly which equally affords the convenience and augmentation of adjacent rung tying with a straight forward and economical structural arrangement which can be readily manufactured, assembled and maintained with a minimum of operating steps required of the extension ladder user, further enhancing rung lock structure to limit moveability of such structure when in operating position.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.